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| Gay, Melanie; Berthe, Franck; Leroux, Frederique. |
| In an attempt to develop a reproducible experimental model of bacterial infection in Crassostrea gigas, oysters taken from very localised sub-populations suffering natural mortality outbreaks were used in cohabitation trials under laboratory conditions. From these trials, a collection of Vibrio strains was isolated from moribund and healthy oysters. In a second step, strains were experimentally tested for virulence by means of injection into healthy oysters. This screening revealed a span of virulence among isolated strains from none to medium. When pooling injected strains, results suggest increased virulence. Vibrio strains may have additive/synergistic action leading to higher C, gigas mortality rates in experimental challenges. Although the study... |
| Tipo: Text |
Palavras-chave: Crassostrea gias; Antagonism; Agonism; Virulence; Vibrio splendidus. |
| Ano: 2004 |
URL: http://archimer.ifremer.fr/doc/2004/publication-3174.pdf |
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| Goarant, Cyrille; Reynaud, Yann; Ansquer, Dominique; De Decker, Sophie; Saulnier, Denis; Leroux, Frederique. |
| A collection of 57 isolates of Vibrio nigripulchritudo from either diseased or healthy shrimp and from shrimp farms environment was studied in order to gain a better understanding of the epidemiology of this pathogen, notably isolated from two distinct shrimp disease complexes. Molecular typing using two different techniques, arbitrarily primed PCR (AP-PCR) and multi-locus sequence typing (MLST), studied together with experimental pathology data allowed a relevant epidemiological insight into this possibly emerging pathogen. Additionally, results obtained with the two molecular typing techniques were congruent and allowed discriminating the strains associated with the "Summer Syndrome" from strains isolated from other contexts, especially the other shrimp... |
| Tipo: Text |
Palavras-chave: Virulence; Epidemiology; Typing; MLST; AP PCR; Mariculture; Vibriosis. |
| Ano: 2006 |
URL: http://archimer.ifremer.fr/doc/2006/publication-1913.pdf |
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| Paillard, Christine; Leroux, Frederique; Borrego, Juan. |
| The main microbial diseases affecting marine cultured bivalves have been revised on the basis of the etiologic agents, pathogenesis and pathogenicity. Several recent bivalve-interaction models have been studied, including Pecten larvae-Vibrio pectinicida, brown ring disease, juvenile oyster disease, Pacific oyster nocardiosis and summer mortalities of oysters. In addition, the taxonomy and phylogeny of new potential bivalve pathogens and their virulence factors have been established. Facing the difficulty of identifying bacterial strains associated with molluscan diseases (mainly vibriosis), polyphasic approaches have been developed to correlate the phenotype and genotype of potential pathogens. By evaluating likely virulence mechanisms, developing... |
| Tipo: Text |
Palavras-chave: Diagnostic tools; Virulence factors; Pathogenicity; Pathogenesis; Etiology; Bivalve mollusc; Vibriosis. |
| Ano: 2004 |
URL: http://archimer.ifremer.fr/doc/2004/publication-407.pdf |
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| Faury, Nicole; Saulnier, Denis; Thompson, F; Gay, Melanie; Swings, J; Leroux, Frederique. |
| Polyphasic analysis of five new Vibrio isolates originating from the haernolymph of diseased cultured oysters is described. The new isolates were closely related to Vibrio splendidus, having 98 % 16S rRNA gene sequence similarity. gyrB phylogenetic analysis, fluorescent amplified-fragment length polymorphism (FAFLP) fingerprinting and DNA-DNA hybridization experiments clearly showed that the new isolates form a tight genomic group that is different from the currently known Vibrio species. It is proposed to accommodate these isolates in a novel species, Vibrio crassostreae sp. nov. (type strain LGP 7(T) =LMG 22240(T)=Clp 108327(T)). Phenotypic and chemotaxonomic features that differentiate V. crassostreae from other known Vibrio species include arginine... |
| Tipo: Text |
Palavras-chave: Identification; Vibrio; Crasssotrea gigas; Ostreiculture. |
| Ano: 2004 |
URL: http://archimer.ifremer.fr/doc/2004/publication-591.pdf |
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| Samain, Jean-francois; Degremont, Lionel; Soletchnik, Patrick; Haure, Joel; Bedier, Edouard; Ropert, Michel; Moal, Jeanne; Huvet, Arnaud; Bacca, Helene; Van Wormhoudt, A; Delaporte, Maryse; Costil, K; Pouvreau, Stephane; Lambert, Christian; Boulo, Viviane; Soudant, Philippe; Nicolas, Jean-louis; Leroux, Frederique; Renault, Tristan; Gagnaire, Beatrice; Geret, Florence; Boutet, Isabelle; Burgeot, Thierry; Boudry, Pierre. |
| Summer mortality of Pacific oysters is known in several countries. However no specific pathogen has been systematically associated with this phenomenon. A complex combination of environmental and biological parameters has been suggested as the cause and is now starting to be identified. A high genetic basis was found for survival in oysters when a first generation (G1) was tested in three sites during summer. This paper presents a synthesis on physiological characteristics of two selected groups ('R' and 'S', from families selected for resistance and susceptibility to summer mortality respectively), of the second and third generations. R and S showed improvement or reduction of survival compared with the control in both field and laboratory trials... |
| Tipo: Text |
Palavras-chave: ROS; Temperature; Stress; Hemocytes; Reproduction; Genetic selection; Resistant oyster; Crassostrea gigas; Pacific Oyster; Summer mortality. |
| Ano: 2007 |
URL: http://archimer.ifremer.fr/doc/2007/publication-2809.pdf |
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| Leroux, Frederique; Binesse, Johan; Saulnier, Denis; Mazel, Didier. |
| splendidus is a dominant culturable Vibrio in seawater, but strains related to this group are also associated with mortalities in a variety of marine animals. The determinants encoding the pathogenic properties of these strains are still poorly known, however, the recent sequencing of the genome of V. splendidus LGP32, an oyster pathogen, offers the opportunity to decipher the basis of the virulence properties by the disruption of candidate genes. We have developed a novel suicide vector based on the pir-dependant R6K replicative origin, which can be transferred by RP4 based conjugation to, potentially, any Vibrio strain, and which also carries the plasmid F toxin ccdB gene under the control of the PBAD promoter. We demonstrate that this genetic system... |
| Tipo: Text |
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| Ano: 2007 |
URL: http://archimer.ifremer.fr/doc/2007/publication-3292.pdf |
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| Berthe, Franck; Leroux, Frederique; Adlard, Robert; Figueras, Antonio. |
| Among mollusc pathogens, paramyxeans are an important group of protistan parasites belonging to the genera Marteilia and Marteilioides. Martelia refringens and M. sydneyi are of particular concern given their potential impact on mollusc aquaculture world-wide. Aber disease and QX disease are currently listed by the OIE, the World Organisation for Animal Health. After more than thirty years of existence in the scientific literature, these organisms still pose questions and research challenges to investigators. This paper reviews current knowledge of the group and key references. The review was focused on taxonomy, epidemiology, pathology and potential control methods for these organisms in order to enhance understanding of paramyxean infection issues in... |
| Tipo: Text |
Palavras-chave: Paramyxean parasites; Diagnosis; Pathology; Epidemiology; Taxonomy. |
| Ano: 2004 |
URL: https://archimer.ifremer.fr/doc/2004/publication-406.pdf |
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| Fabioux, Caroline; Pouvreau, Stephane; Leroux, Frederique; Huvet, Arnaud. |
| The vasa gene is,a key determinant for germline formation in eukaryotes. This gene, highly conserved through evolution, encodes a RNA helicase protein member of the DEAD-box family. To understand the germline formation in oyster, we report here the isolation and the characterization of a vasa orthologue in Crassostrea gigas (Oyvlg). OyVLG contained the eight consensus domains of the DEAD-box including those providing RNA unwinding activity. The expression pattern of Oyvlg was examined in adult oyster tissues at different reproductive stages. Its expression was restricted to germline cells both in males and females, including germinal stem cells and auxiliary cells. The expression of Oyvlg, strongest in early germ cells, decreased as the maturation... |
| Tipo: Text |
Palavras-chave: RNA helicase; DEAD box; Vasa; Germline; Gametogenesis; Oyster. |
| Ano: 2004 |
URL: http://archimer.ifremer.fr/doc/2004/publication-646.pdf |
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